P0305 on Ford
Cylinder 5 Misfire Detected
P0305 on Ford vehicles indicates cylinder 5 misfire detected. Au7o has documented this code across 4 Ford models — most commonly on Bronco Sport, Crown Victoria, Expedition. This code means the engine control module detected a misfire on cylinder number 5, meaning that cylinder is not burning its air-fuel mixture properly on some combustion cycles. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder fails to fire correctly. A misfire wastes fuel, can make the engine run rough or shake, and dumps unburned fuel into the exhaust, which can overheat and damage the catalytic converter. It generally points to a problem with spark, fuel delivery, or compression specifically affecting cylinder 5. Typical repair costs on Ford range from $150 to $7,500, depending on the specific model and root cause.
Common Causes of P0305
- •Worn or fouled spark plug on cylinder 5
- •Failed ignition coil or coil pack for cylinder 5
- •Faulty or clogged fuel injector on cylinder 5
- •Vacuum or intake air leak affecting that cylinder
- •Bad spark plug wire or boot (on applicable engines)
- •Low compression from worn rings, valves, or head gasket
- •Carbon buildup or sticking valve on cylinder 5
- •Lean or rich fuel condition affecting the cylinder
P0305 on Ford by Model
Ford Bronco Sport(1 issue)
- 1.5L EcoBoost 3-Cylinder Coolant Loss and Engine Failure2021-2024
The 1.5L EcoBoost 3-cylinder engine in 2021-2024 Ford Bronco Sport is the latest variant of Ford's troubled EcoBoost coolant intrusion problem. The open-deck block design allows coolant to leak internally into the cylinders, causing misfires, white exhaust smoke, and complete engine failure. Ford issued TSB 25-2063 in February 2025 addressing coolant loss in 2021-2024 Bronco Sport 1.5L models, recommending a coolant system flush to prevent recurrent water pump failures. Ford also extended warranty coverage to 7 years/84,000 miles for short block replacement due to coolant intrusion. BroncoSportForum.com documents numerous cases including owners stranded with brand-new vehicles. NHTSA opened an investigation into EcoBoost engine failures in October 2023 covering multiple Ford models.
Ford Crown Victoria(1 issue)
- 4.6L 2-Valve Spark Plug Ejection/Breakage1992-2011
The 4.6L 2-valve engine uses spark plugs that thread into aluminum heads with only a few threads of engagement. The plugs can eject from the head under load, stripping the threads. Later models (2004+) use a 2-piece plug design that can break during removal.
Ford Expedition(1 issue)
- 5.4L 2-Valve Spark Plug Blow-Out From Cylinder Head1997-2008
The 5.4L Triton 2-valve V8 in 1997-2008 Expeditions is notorious for spark plugs ejecting from the aluminum cylinder heads. The 2-valve heads have only 4 threads holding each spark plug, which is insufficient for the clamping force needed. Over time, the threads strip and the spark plug launches out of the head under combustion pressure, taking the ignition coil with it. This typically happens when spark plugs are removed and reinstalled, or spontaneously at high mileage.
Ford Freestar(1 issue)
- Ignition Coil Pack Failure2004-2007
The coil-on-plug ignition coils on the 3.9L and 4.2L V6 engines fail frequently, causing misfires, rough running, and reduced fuel economy. Often one coil fails and the others follow shortly.
Looking for P0305 on a different make?
View P0305 across all makes →Frequently Asked Questions
What does P0305 mean on Ford?▼
P0305 stands for "Cylinder 5 Misfire Detected." This code means the engine control module detected a misfire on cylinder number 5, meaning that cylinder is not burning its air-fuel mixture properly on some combustion cycles. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder fails to fire correctly. A misfire wastes fuel, can make the engine run rough or shake, and dumps unburned fuel into the exhaust, which can overheat and damage the catalytic converter. It generally points to a problem with spark, fuel delivery, or compression specifically affecting cylinder 5. On Ford specifically, this code is documented across 4 models.
What causes P0305 on Ford vehicles?▼
Common causes on Ford: Worn or fouled spark plug on cylinder 5, Failed ignition coil or coil pack for cylinder 5, Faulty or clogged fuel injector on cylinder 5, Vacuum or intake air leak affecting that cylinder, Bad spark plug wire or boot (on applicable engines). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0305 on a Ford?▼
Repair costs on Ford range from $150 to $7,500, depending on the specific model and root cause.
Which Ford models have P0305 documented?▼
Au7o has documented P0305 on 4 Ford models: Bronco Sport, Crown Victoria, Expedition, Freestar.